diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 22a4b687ea5b4b3cb9d576bfeffaed813256a795..bbf4ee6c96dac1ed33e280fdc21bb56677727b13 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -167,7 +167,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	acpi=		[HW,ACPI,X86,ARM64]
 			Advanced Configuration and Power Interface
-			Format: { force | off | strict | noirq | rsdt }
+			Format: { force | off | strict | noirq | rsdt |
+				  copy_dsdt }
 			force -- enable ACPI if default was off
 			off -- disable ACPI if default was on
 			noirq -- do not use ACPI for IRQ routing